8328261: public lookup fails with IllegalAccessException when used while module system is being initialized

Reviewed-by: rriggs, alanb

Author: Mandy Chung

src/java.base/share/classes/sun/invoke/util/VerifyAccess.java

@@ -201,9 +201,10 @@ public static boolean isClassAccessible(Class<?> refc,
             Module lookupModule = lookupClass.getModule();
             Module refModule = refc.getModule();
 
-            // early VM startup case, java.base not defined
-            if (lookupModule == null) {
-                assert refModule == null;
+            // early VM startup case, java.base not defined or
+            // module system is not fully initialized and exports are not set up
+            if (lookupModule == null || !jdk.internal.misc.VM.isModuleSystemInited()) {
+                assert lookupModule == refModule;
                 return true;
             }
 
@@ -230,11 +231,6 @@ public static boolean isClassAccessible(Class<?> refc,
             if (isModuleAccessible(refc, lookupModule, prevLookupModule))
                 return true;
 
-            // not exported but allow access during VM initialization
-            // because java.base does not have its exports setup
-            if (!jdk.internal.misc.VM.isModuleSystemInited())
-                return true;
-
             // public class not accessible to lookupClass
             return false;
         }